7926

• UCREFRP Catalog Number: 7926
• Author: Annear, T. C. and A. L. Conder.
• Title: Relative Bias of Several Fisheries Instream Flow Methods.
• USFW Year: n.d.
• USFW - Doc Type: Cheyenne, Wyoming.
• Copyright Material: NO

siderations. The convenience of the Tennant method is an asset where fast,

liminary recommendations are needed.

The wetted perimeter method bases results on site-specific hydrologic infort

mation and subsequently possesses an assumption that wetted perimeter

reflect unique fish habitat dynamics in response to changes in flow.

logical assumption, however, it is not well documented in the literature.

Biologists using this method may have a difficult time convincing otherb"::;~utside

the fisheries profession that this assumption is valid without suppqrting field

observations.

Use of the curve may not be as much of a concern as the selection of a point

on the curve for the MF recommendation. Certainly the four statistically based

methods we used are defensible, each for its own reasoning, however, an imagina-

tive user could conceivably derive a great many more for other equally defen-

sible reasons. This is not necessarily a handicap as long as the user's reason

for using a statistical method is logical and defensible.

Subjectively identified inflection points resulted in fairly high numbers of

unbiased recommendation,s,' though no significant tendencies ,were found.

Still ,

without supporting field observations, a biologist is basically asking others to

trus t his judgment.

This may be especially true where no clearly defined

inflection point exists or where several inflection points exist on a curve.
'I 0"0

Our inability to show significant numbers of unbiased recommendations or

significant tendencies should not necessarily be viewed as a measure of the

the the .....etted perimeter methods in this study relative to real

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